The present invention generally relates to a device and method for deterring misuse of copying machines, particularly xerographic copying machines of the type including a glass platen on which a document is placed and is thereby copied by the machine. Accordingly, in an embodiment of the present invention, a transparent member bearing a secondary image is preferably provided in juxtaposition with the glass platen so that when the document is placed on the glass platen, the primary and secondary images will be concurrently reproduced and appear on the document copy.
With the advent of xerography, and particularly the widespread use of xerographic copying machines, unauthorized personal use of such machines has become a major problem for businesses. For example, considerable costs are incurred by any business which utilizes xerographic copying machines due to employee misuse of the machines for personal reasons. The costs are not only associated with the actual material cost of operating the copying machines, such as, costs in the form of paper and electrical power, but such costs are also attributable to wasted employee time in utilizing the copy machines for personal use during regular business hours. Accordingly, the cost of copying machine misuse can be substantial over a period of time. Additionally, in view of the fact that most employee personal use of the xerographic copying machines occurs during regular business hours, that time is unproductive for the business and is therefore a detriment to the company's productivity.
Therefore, a practical and economically feasible system has been needed which deters misuse of copying machines. The logic behind the need for such a deterrent system is twofold. First, the actual material costs of operating the machines for personal employee use would be saved. Secondly, that portion of the employee's time which is devoted to personal use of the copy machine would be similarly saved thereby increasing that employee's productivity and benefitting the overall productivity of the company.
Prior systems for deterring copying machine misuse have tended to be extremely complex. For example, it has been proposed to interlock the copying machine with an electronic control unit so that the machine cannot be activated except by a special coded card issued to each authorized employee. When the employee inserts his card into the control unit, a discrete employee number is automatically encoded thereby activating the machine. The number of copies which that employee makes can therefore be recorded and the monthly summaries of copy machine use can be printed for each employee to identify potential misuse of the machine.
However, such an electronic system is expensive to purchase, maintain, and operate. Consequently, such a system does not lend itself to smaller businesses where the need to prevent misuse of copying machines is similarly apparent. Thus, for smaller businesses, this need must go unanswered due to the exorbitant cost of prior deterrent systems.
It has been proposed in the photographic art to provide an identification system for light-sensitive photographic film or the like so that a particular camera number, for example, can be transferred to the light-sensitive negative. See, U.S. Pat. Nos. 4,123,767 to Halpern; 4,193,684 to Armstrong; and 1,506,361 to Bulask. Document security systems to deter forgeries or alterations of an original document have also been proposed as exemplified by U.S. Pat. Nos. 3,802,724 to Gosnell and 4,265,469 to Mowry, Jr., et al. However, each of the above prior art proposals, of course, is not suitable for today's modern xerographic copying machines.
U.S. Pat. No. 4,251,152 proposes that two or more different latent electrostatic images can be formed on a dielectric or photoconductive material. According to this prior art, a first image that is to be repeated on a drum is placed together with a second independent charging corona system which continually provides a new address at a particular point on the first image and a separate means for removing only that address. Thus, the multi-image formation proposed by U.S. Pat. No. 4,251,152 is highly specialized and, once again, does not lend itself for use by small businesses. Additionally, this prior art proposal is not readily interchangeable among the extreme varieties of conventionally known xerographic equipment presently on the market.
However, according to the present invention, a device for deterring misuse or unauthorized use of a xerographic copying machine is provided which is inexpensive, easily produced, and can be readily tailored for use with virtually all known xerographic copying machines and thus, marks a distinct advance in the art.
Conventional copying machines utilize a rigid transparent glass platen on which a document having a primary image to be copied is registrable. The document is therefore placed with the primary image against the glass platen and the copying machine operated so that the particular copying means associated with the machine produces a copy of the document primary image.
According to the present invention, a transparent substrate is preferably provided for operative juxtaposition with the glass platen and includes a secondary image thereon. Thus, the transparent substrate according to the present invention can be placed on the glass platen so that when the primary image of the document is copied, the secondary image will also be concurrently copied. Suitable secondary images which can be utilized according to the present invention can include any indicia, company logo, trademark or other identifying marks, words or the like. Preferably, the secondary image is dense enough so that it is reproducible over a range of copy machine background settings yet is fine enough so that the primary image of the document being copied is readily and visibly perceptible.
Therefore, the present invention provides a novel device for efficiently and economically converting virtually all presently known xerographic copying machines so that unauthorized use thereof can be significantly deterred, if not completely alleviated.
Other aspects and advantages of the present invention will become more apparent from the detailed description of the preferred exemplary embodiments which follows.